The CyberSquad and Slider need to purchase an Alpha deck. When they hear the price, they calculate if they'll have enough snelfus to purchase the two remaining parts for the syncalator. Since they don't have time to wait for a used Alpha deck that is significantly cheaper, they purchase it and verify that they've received the correct amount of change from the salesperson.
The CyberSquad, Digit, and Slider decide they need to save up 100 snelfus within 11 days in order to buy an encrypted chip and save Motherboard. They calculate how many snelfus they need to save each day and then get jobs so they can put money into their savings.